package com.dog.basics.common.util;

import cn.hutool.core.io.IoUtil;
import cn.hutool.core.util.StrUtil;
import cn.hutool.poi.excel.ExcelWriter;
import org.apache.poi.openxml4j.exceptions.InvalidFormatException;
import org.apache.poi.ss.usermodel.*;
import org.springframework.web.multipart.MultipartFile;

import javax.servlet.ServletOutputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;

public class POIUtil {

    private final static String xls = "xls";
    private final static String xlsx = "xlsx";
    private final static String csv = "csv";

    /**
     * 读入excel文件，解析后返回
     *
     * @param file
     * @throws IOException
     */
    public static List<String[]> readExcel(MultipartFile file) throws IOException, InvalidFormatException {
        //检查文件
        checkFile(file);
        //获得Workbook工作薄对象
        Workbook workbook = getWorkBook(file);
        //创建返回对象，把每行中的值作为一个数组，所有行作为一个集合返回
        List<String[]> list = new ArrayList<String[]>();
        if (workbook != null) {
            for (int sheetNum = 0; sheetNum < workbook.getNumberOfSheets(); sheetNum++) {
                //获得当前sheet工作表
                Sheet sheet = workbook.getSheetAt(sheetNum);
                if (sheet == null) {
                    continue;
                }
                //获得当前sheet的开始行
                int firstRowNum = sheet.getFirstRowNum();
                //获得当前sheet的结束行
                int lastRowNum = sheet.getLastRowNum();
                //循环除了第一行的所有行
                for (int rowNum = firstRowNum + 1; rowNum <= lastRowNum; rowNum++) {
                    //获得当前行
                    Row row = sheet.getRow(rowNum);
                    if (row == null) {
                        continue;
                    }
                    //获得当前行的开始列
                    int firstCellNum = row.getFirstCellNum();
                    //获得当前行的列数
                    int lastCellNum = row.getPhysicalNumberOfCells();
                    String[] cells = new String[row.getPhysicalNumberOfCells()];
                    //循环当前行
                    for (int cellNum = firstCellNum; cellNum < lastCellNum; cellNum++) {
                        Cell cell = row.getCell(cellNum);
                        cells[cellNum] = getCellValue(cell);
                    }
                    list.add(cells);
                }
            }
            workbook.close();
        }
        return list;
    }


    /**
     * 导出ex表格
     *
     * @param writer guonh 2020年2月7日
     */
    public static void createExcel(ExcelWriter writer, String filenName) {
        //out为OutputStream，需要写出到的目标流
        //response为HttpServletResponse对象
        //utf-8
        HttpContextUtils.getHttpServletResponse().setCharacterEncoding("utf-8");
        HttpContextUtils.getHttpServletResponse().setContentType("application/vnd.ms-excel;charset=utf-8");
        //test.xls是弹出下载对话框的文件名，不能为中文，中文请自行编码
        HttpContextUtils.getHttpServletResponse().setHeader("Content-Disposition", StrUtil.format("attachment;filename={}.xls", StrUtil.isNotBlank(filenName) ? filenName : "template"));
        ServletOutputStream out = null;
        try {
            out = HttpContextUtils.getHttpServletResponse().getOutputStream();
            writer.flush(out, true);
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            // 关闭writer，释放内存
            writer.close();
            //此处记得关闭输出Servlet流
            IoUtil.close(out);
        }
    }

    public static void checkFile(MultipartFile file) throws IOException {
        //判断文件是否存在
        if (null == file) {
            throw new FileNotFoundException("文件不存在！");
        }
        //获得文件名
        String fileName = file.getOriginalFilename();
        //判断文件是否是excel文件
        if (!fileName.endsWith(xls) && !fileName.endsWith(xlsx)) {
            throw new IOException(fileName + "不是excel文件");
        }
    }

    /**
     * 导出ex表格
     *
     * @param workbook guonh 2020年2月7日
     */
    public static void createEasyExcel(Workbook workbook, String filenName) {
        //out为OutputStream，需要写出到的目标流
        //response为HttpServletResponse对象
        //utf-8
        HttpContextUtils.getHttpServletResponse().setCharacterEncoding("utf-8");
        HttpContextUtils.getHttpServletResponse().setContentType("application/vnd.ms-excel;charset=utf-8");
        //test.xls是弹出下载对话框的文件名，不能为中文，中文请自行编码
        HttpContextUtils.getHttpServletResponse().setHeader("Content-Disposition", StrUtil.format("attachment;filename={}.xls", StrUtil.isNotBlank(filenName) ? filenName : "template"));
        ServletOutputStream out = null;
        try {
            out = HttpContextUtils.getHttpServletResponse().getOutputStream();
            workbook.write(out);
        } catch (IOException e) {
            e.printStackTrace();
        } finally {

            //此处记得关闭输出Servlet流
            IoUtil.close(out);
        }
    }

    public static Workbook getWorkBook(MultipartFile file) throws IOException, InvalidFormatException {
        //获得文件名
        String fileName = file.getOriginalFilename();
        //创建Workbook工作薄对象，表示整个excel
        Workbook workbook = null;

        //获取excel文件的io流
        InputStream is = file.getInputStream();
        //根据文件后缀名不同(xls和xlsx)获得不同的Workbook实现类对象
        if (fileName.endsWith(xls) || fileName.endsWith(xlsx)) {
            workbook = WorkbookFactory.create(is);
        }
        return workbook;
    }

    public static String getCellValue(Cell cell) {
        String cellValue = "";
        if (cell == null) {
            return cellValue;
        }
        //把数字当成String来读，避免出现1读成1.0的情况
        if (cell.getCellType() == CellType.NUMERIC) {
            cell.setCellType(CellType.STRING);
        }
        //判断数据的类型
        switch (cell.getCellType()) {
            case NUMERIC: //数字
                cellValue = String.valueOf(cell.getNumericCellValue());
                break;
            case STRING: //字符串
                cellValue = String.valueOf(cell.getStringCellValue());
                break;
            case BOOLEAN: //Boolean
                cellValue = String.valueOf(cell.getBooleanCellValue());
                break;
            case FORMULA: //公式
                cellValue = String.valueOf(cell.getCellFormula());
                break;
            case BLANK: //空值
                cellValue = "";
                break;
            case ERROR: //故障
                cellValue = "非法字符";
                break;
            default:
                cellValue = "未知类型";
                break;
        }
        return cellValue;
    }
}
